Influenza is an infectious disease which is-prevalent in the world almost every year. Many people are infected with influenza every year despite the existence of vaccine and suffer from fever, headache, musculus arthralgia and the like. Further they are inflicted with complications, i.e. influenza brain inflammation and encephalopathy and may die of the complication in the worst case. The influenza virus is so feared despite the existence of vaccine because influenza virus tends to cause gene mutation, leading to change of antigen form so that the antibody increased in the body by vaccine fails to recognize it, and the effect of vaccine is lowered. As described above, even if it is predictable what type of influenza will prevail every year, a problem is raised in that a proper vaccine can not be rapidly supplied since a new type of virus will be generated all at once. In this situation, it is necessary to develop a highly effective drug which can show high effects on various kinds of influenza viruses. In recent years, the infection mechanism of influenza viruses have been clarified in terms of molecule levels and gene levels due to marked progress of scientific technology. It is now under way to prepare various kinds of influenza virus infection inhibitors.
The infection of influenza viruses and the mechanism of growth are as follows. First, a virus is made to invade the living body. On approaching the host cell, a trimer of protein called hemagglutinin on the outer layer of the virus, becomes specifically bonded to a sialyl oligosaccharide, i.e. a receptor on the host cell. The sialyl oligosaccharide contains sialic acid at the end. The sialic acid is chiefly involved in bonding to hemagglutinin. Then a membrane fusion occurs between the virus and the host cell so that the virus makes RNA infected with the host cell. Then, the virus gene is replicated therein for the advent of virus offspring. Then, a virus is germinated outside the host cell to complete the propagation. In germination of a virus, hemagglutinin becomes bonded to sialyl oligosaccharide again. The sialic acid is separated from the sialyl oligosaccharide by sialidase, namely an enzyme, on the outer layer of the same virus, whereby germination can be achieved.
Recently new remedies have been developed for inhibiting the activity of sialidase reaction occurring at the last stage of virus infection. These two drugs are available under the names Zanamivir (trade name, Relenza, Glaxo Wellcome) and Oceltamivir phosphate (trade name, Tamiflu, Japanese Roche Corp.). However, these two sialidase inhibitors are able to inhibit the infection at the last stage of infection and are less effective in inhibition because it acts after the growth of a virus has reached the peak. It is desirable to administer the drug within 48 hours after development of infection. Therefore, a compound useful as an effective drug is demanded which inhibits the infection at the first stage at. which the virus is bonded to the host cell.
It is already known that in the development of hemagglutinin inhibitors, when a polyvalent sialyl oligosaccharide derivative having a number of sialyl oligosaccharides in a molecule shows a higher inhibiting activity against an influenza virus than a monovalent sialyl oligosaccharide derivative. This is because an affinity between a ligand and a receptor is more increased when polyvalent molecules having a plurality of sialyl oligosaccharide derivatives are bonded thereto than when plural monovalent sialyl oligosaccharide derivatives are bonded to numerous hemagglutinins existing on the surface of the virus.
Up to date, a multiplicity of polyvalent sialyl oligosaccharide derivatives have been developed with the expectation of such effect. Kanie et al prepared a styrene polymer (1) having sialyl lactose bonded thereto and researched the relation of the polymer with influenza. It was found that the polymer exhibits inhibition activity 1,000 times as high as fetuin which is a sialyl oligosaccharide protein.

Whitesides et al synthesized a polyacrylamide polymer (2) having a sialic acid derivative bonded and showed that the higher the molecular weight of the polymer is, the higher the inhibition activity is.

However, the polymer, i.e. high molecular weight compound, is a mixture of polymers having different molecular weights and thus has a structure which is not clear. If the compound contains a polymer having a molecular weight of 60 KDa or higher, the polymer remains in the body since it has too high a molecular weight to be removed from the body. Specifically it can not be passed through Bowman's capsules in Malpighian corpuscles of the kidney, so that the balance of metabolism in the liver is thrown. Thus, the defect is likely to do harm to the human body. For this possibility, FDA (The Food Drug Administration) does not approve the compounds like such polymer type for the safety problem even if the compound is an effective influenza infection inhibitor. An object of the invention is to provide a novel asparagine-linked disialoundecaoligosaccharide-fatty acid amide, and a composition or a drug containing the same.
Another object of the invention is to provide a drug for preventing and/or curing virus diseases such as influenza virus. infectious diseases, the drug having a high activity of inhibiting the virus infection and/or the growth.